A marine GPS is a necessity, especially if you sail on large lakes ... On the other hand, if you are boating on inland lakes, non-mapping is probably a better choice. So, what is the difference? A non ...

GPS frequency: 1575.42 ± 5MHz, Beidou frequency: 1561 ± 5MHz. Compatible with Boat Ship Marine GPS Navigation System Unit Modem Receiver Transducer Explorer Fish finder Sounder. External Marine ...